general: Use deducation guides for std::lock_guard and std::unique_lock

Since C++17, the introduction of deduction guides for locking facilities
means that we no longer need to hardcode the mutex type into the locks
themselves, making it easier to switch mutex types, should it ever be
necessary in the future.

src/input_common/keyboard.cpp

@@ -36,18 +36,18 @@ struct KeyButtonPair {
 class KeyButtonList {
 public:
     void AddKeyButton(int key_code, KeyButton* key_button) {
-        std::lock_guard<std::mutex> guard(mutex);
+        std::lock_guard guard{mutex};
         list.push_back(KeyButtonPair{key_code, key_button});
     }
 
     void RemoveKeyButton(const KeyButton* key_button) {
-        std::lock_guard<std::mutex> guard(mutex);
+        std::lock_guard guard{mutex};
         list.remove_if(
             [key_button](const KeyButtonPair& pair) { return pair.key_button == key_button; });
     }
 
     void ChangeKeyStatus(int key_code, bool pressed) {
-        std::lock_guard<std::mutex> guard(mutex);
+        std::lock_guard guard{mutex};
         for (const KeyButtonPair& pair : list) {
             if (pair.key_code == key_code)
                 pair.key_button->status.store(pressed);
@@ -55,7 +55,7 @@ public:
     }
 
     void ChangeAllKeyStatus(bool pressed) {
-        std::lock_guard<std::mutex> guard(mutex);
+        std::lock_guard guard{mutex};
         for (const KeyButtonPair& pair : list) {
             pair.key_button->status.store(pressed);
         }